A larger amount of palatable food is needed to provide stress relief during Western diet-induced obesity

Many individuals eat highly palatable foods to cope with stress, and this so-called 'comfort' feeding occurs to a greater extent in people who are overweight and obese. To study this relationship, we previously characterized a limited sucrose intake (LSI) paradigm that reduces hypothalamic-pituitary-adrenocortical (HPA) axis stress responses in normal weight rats, but not in those with Western diet-induced obesity (DIO). The present work tests the hypothesis that a larger volume of sucrose drink recovers effective HPA blunting during obesity. Time-limited sucrose access, in which sucrose was offered in an unlimited volume for 30 min twice-daily to chow-fed lean and Western DIO rats for 2 weeks, resulted in greater sucrose drink intake than that allowed in the LSI paradigm (4 ml/twice-daily session) and reduced post-stress plasma corticosterone relative to water controls in both lean and DIO rats. Likewise, when given volume-limited access to a larger sucrose volume (6 ml vs. the standard 4 ml per twice-daily session) the 6 ml volume reduced post-stress plasma corticosterone relative to water controls, in both lean and DIO rats, whereas the 4 ml volume was only effective in lean rats. These data replicate that the typical LSI sucrose volume does not produce effective stress-blunting during Western DIO, and extend this to show that larger sucrose volumes, given via either time- or volume-limited access paradigms, recovers this effect. This suggests that stress-related eaters with obesity may require larger amounts of palatable foods to maintain adequate stress relief.